Poems of Cells
by Pidgeapodge
Summary: Eosinophil has lost a book. A book that is very, very important to her. A book that must be kept top-secret at all costs. Can her friends help her find it before it falls into the wrong hands?
1. Chapter 1: The Missing Book

**Chapter 1: The Missing Book**

Red Blood Cell AE-3803 jogged quickly down the artery with her cart of oxygen. She took a left into a capillary, and squeezed her way down to an apartment at the end. She rang the doorbell.

 _DING-DONG_.

A Normal Cell answered the door.

"Good morning! Your oxygen has arrived!" Red Blood Cell said.

"Thanks for coming through such a tight area. I know it's a bit of a squeeze," said the Cell Boy.

"No problem at all! It's all part of the job! Have a nice day!" she replied with a smile.

The Cell Boy laughed. "You're always so happy! I look forward to deliveries from you, they make my day."

AE-3803 almost stepped back in surprise, but the capillary restricted her movement. Instead, she proceeded to attempt an awkward bow in response to the cell's praise.

"Th- Thank you very much!" she said, gratitude flooding her heart.

She collected the Cell Boy's signature and excess carbon dioxide, squeezed her way out of the corridor, and made it out into the more open space of the connecting vein. She briefly took off her red jacket, reversing it so that the dark red side displays on the outside, while the bright red side was inside, indicating that she was now transporting the useless carbon dioxide to the lungs for disposal. With her jacket back on, she began on her way.

Then she stopped.

"Hmm… now which way is it?" she wondered aloud.

Just as she was pulling out her map, she heard a familiar voice.

"Big sister Red Blood Cell! Big sister Red Blood Cell!" a child's voice rang out.

3803 looked around for the source of the noise. She quickly saw the Platelet Leader waving and calling out to her. Leader-chan was being carried with her little friend wearing the backwards cap on the shoulders of a very familiar person.

"Hey, Red Blood Cell. How are you doing?" asked White Blood Cell U-1146. He walked up to 3803 at a leisurely pace.

3803 felt warmth rush into her chest. She and 1146 spent lots of time together, at least when they could spare it. He was very special to her, and she had no idea how to repay him for always helping her.

And, of course, the platelets were adorable. One could never _not_ be overjoyed to see them.

"Platelet-chan! White Blood Cell! Good morning!" 3803 called out while they were approaching.

"Don't forget about me!" called the platelet with the backwards hat.

"Oh… I'm sorry, but I don't know what to call you," said 3803.

"Just call me Backwards Cap-kun. Everyone else does!" the young boy replied cheerfully.

"Okay! Pleased to meet you, Backwards Cap-kun!" said 3803, reaching up to shake his hand.

"Big sister, where are you headed to?" asked the Platelet girl.

"I'm going to deliver this carbon dioxide to the lungs… do you wanna ride?"

AE-3803 thought that White Blood Cell was probably getting tired from carrying the platelets around.

"Yayyy!" shouted the platelets as they scrambled down White Blood Cell and onto the box on Red Blood Cell's cart.

White Blood Cell groaned dramatically and stretched his arms. "I can walk with you all," he said. "You never know if an antigen will-"

He did not finish that thought before the radar on his hat popped up, alerting them to an approaching antigen. White Blood Cell drew his knife in a flash, immediately dropping into an attack stance, his eyes searching for the unseen attacker.

Suddenly, a giggling bacterium rounded the corner of a building.

The bacterium did not even have time to look their way as White Blood Cell shouted "ANTIGEN SIGHTED!" and pounced. Slashing his knife downward, he cleaved the germ in two. It barely got out a scream as cytoplasm spurted everywhere and the two halves fell down, unmoving.

White Blood Cell heaved as he stood over the bacterium. In the calm following his attack, he could hear something.

It sounded like… a woman screaming.

Screeching at the top of her lungs, a young woman wearing an entirely pink uniform, with blonde hair tied into two pigtails rounded the corner, a double-pointed spear pointed right at White Blood Cell.

"AAAAAAAAAAHHHH!" she shouted.

"Whoa, WHOA, EOSINOPHIL, LOOK OUT!" White Blood Cell screeched.

Just in time, the woman lifted her spear so that the points were facing away from White Blood Cell. Unfortunately, she was too late to stop her momentum. Inertia carried her forward, so that she slammed full-force into White Blood Cell, knocking them both to the ground.

The woman quickly rolled off of White Blood Cell. Red Blood Cell ran over to help him stand up. She had met the woman in pink before.

"I'm sorry, I'm so, so sorry!" apologized Eosinophil, bowing low.

"It's okay, I'm fine," replied White Blood Cell.

"Eosinophil, what happened? Why were you running after a bacterium?" asked Red Blood Cell.

Eosinophil flushed. "Uh, w-well… um…"

Red Blood Cell cocked her head. Poor Eosinophil's face was now a deeper shade of red than her bright pink uniform. Her bright blonde hair really stood out from her skin like this.

Red Blood Cell had met Eosinophil before, so she knew how flustered Eosinophil could get. She wished that Eosinophil could have more confidence. Red Blood Cell thought that Eosinophil was one of the coolest people she had ever met, and that she was also very adorable.

"I… uh… lost something…" Eosinophil said in a barely audible whisper. "I thought the bacterium t-took it… It was the first thing I saw w-when I noticed it was g-gone."

Now Eosinophil looked like she was on the verge of tears.

"Big sister Eosinophil, what did you lose?" asked the Platelet Leader. She and Backwards Cap-kun had approached the three cells.

Eosinophil seemed to calm down in the platelets' presence. At least, she stopped blushing so much.

Pulling down the bill of her cap to obscure her face, she mumbled, "A… a book…"

"What kind of book?" Leader-chan asked, cocking her head.

Eosinophil blushed harder. "Uh, w-well…"

White blood cell looked at Eosinophil sympathetically. "What does it look like, at least?" he asked kindly.

"It's, uh… pink… with red flowers on it…"

Red Blood Cell put her hands up to her face. "Oh my goodness! That sounds so _cute!_ "

She hadn't expected Eosinophil to be able to blush harder, but somehow she did. With a squeak, Eosinophil united the fluffy ear flaps on her hat and pulled them down to cover the sides of her face.

"Don't worry big sister! We'll help find your book!" Backwards Cap-kun loudly said.

"Yeah! We can help!" Leader-chan chimed in.

"Th- thank you very much," Eosinophil whispered. She was doubled over, still pulling her hat down, unable to hide her embarrassment.

"Big sister, why do you need this book so much?" Backwards Cap-kun asked.

At this, Eosinophil simply plopped down on the ground. Still not meeting anyone's eyes, she said, "It's special to me."

A little hand placed itself on Eosinophil's shoulder. Looking up, her eyes brimming with tears, she saw the determined face of Leader-chan.

"Don't worry big sister, we'll help you!"


	2. Chapter 2: The Search Begins

**Chapter 2: The Search Begins**

White Blood Cell U-1146 looked at his traveling companions.

Next to him, pushing a cart of CO2, AE-3803 was happily humming to herself. She bobbed her head to her little song, the red curl on the side of her head bouncing up and down rhythmically. 1146 smiled as he thought she looked very cute.

Maybe if she opened her eyes as she hummed, she would get lost less.

Meanwhile, on top of her CO2 box sat Platelet Leader-chan, kicking her legs and looking side to side to see if she could catch sight of Eosinophil's lost book.

Ahead of them were Eosinophil and Backwards Cap-kun. Eosinophil was frantically scanning every inch she could, with Backwards Cap-kun tailing right behind her.

 _Poor Eosinophil_ , thought 1146. The two of them grew up in the same bone marrow together, and he felt as if she were a sister to him. Even when she was a myelocyte, she was easily flustered and unsure of herself, which may be why he was assigned to help her train every now and then. Although it had been long since they were myelocytes, and Eosinophil had grown more into her own, he still felt very protective of her. It hadn't been very long since the _anisakis_ incident, and many of the cells who weren't there still treated her as if she were a useless immune cell. Even though she tried to ignore them, White Blood Cell knew that the gossip didn't help her self-esteem at all.

 _ **Anisakis**_ _: a species of parasitic worm that lives in marine animals. It can infect humans who eat raw or undercooked seafood, causing nausea and potential allergic reactions. Eosinophils are the immune system's response to multicellular parasites._

What's more, Eosinophil has no idea how to respond to compliments. Praise just flusters her and makes her feel embarrassed, which is the exact opposite of what 1146 wants for his friend.

The five began heading up to the lungs, since that's where Red Blood Cell was headed anyway.

As they walked, they looked for Eosinophil's book. When he heard her describe it, 1146 knew exactly which book she was talking about.

She had recently admitted to him that she would write poems with a band cell senpai, and that even after becoming an adult she would sometimes continue to write. He remembered as myelocytes she would often carry around a book- a pink book with red flowers.

1146 had no doubt that this is the book she lost. He also had now doubt she would be mortified if anyone read it.

Most of all, they had to find it before Dendritic Cell did.

Eventually, the five made it to the heart. Red Blood Cell put her cart in the drop-off area and picked up the box of CO2 as Platelet hopped off. There were many blood cells going through the heart, so they needed be as compact as possible. White Blood Cell picked up Leader-chan, while Eosinophil put Backwards Cap-kun onto her shoulders. Together, they approached the entrance of the Heart's Right Atrium.

 _ **The Human Heart:**_ _The heart pumps blood throughout the body. Red blood cells carrying carbon dioxide enter the heart's right atrium, through which they go into the right ventricle. They exit the right ventricle to go to the lungs, where they receive oxygen. The blood cells then return to the heart, entering the left atrium. From here they enter the left ventricle and exit to deliver oxygen to the rest of the body._

White Blood Cell looked up in awe at the mighty temple before him. Since he could migrate throughout the body, he didn't see the Heart as often as the red blood cells. The magnificent architecture took his breath away. A grand sign read "Right Atrium" in Kanji, hanging above the arching doors. The magnificent red walls flew upwards, meating the curved roof at top. From inside, a steady beat rang out.

1146 could feel that this was a sacred place, an important place in this body. The Heart commanded the utmost reverence from those who enter its chambers.

He glanced down at Red Blood Cell. While before, she was humming a song with a carefree smile, now she wore a serious, contemplative expression. Holding her box, she slowly closed her eyes as hundreds, thousands of other red blood cells crowded around and compressed their little group. Breathing evenly, she slowly opened her eyes and looked with reverent awe at the Heart's splendor. U-1146 could feel the awestruck energy radiating from her soul, as if he was watching her pray. He closed his own eyes, inwardly smiling as he knew that no matter how often she passed through the Heart, his friend would never cease to experience the wonder as if it were her first time ever.

Opening his eyes once more, White Blood Cell tried to adopt Red Blood Cell's spirit as they inched closer to the entrance. Glancing sideways, he saw Eosinophil with Backwards Cap-kun, both staring wide-eyed at the grandiose display before them. On his own shoulders, he could feel Leader-chan's breathing become slow and even. He imagined she was feeling the same as the others.

With the ever-present beat of the heart keeping time, the five finally entered the Right Atrium.

 _BONG. BONG. BONG._

The beat became much louder inside the Heart. The outside light quickly faded, making the interior dim and difficult to see. Blood cells pushed in at all sides.

With a determined gleam in her eye, AE-3803 forged ahead.

"Big Brother White Blood Cell, we need to stay together!" Platelet-chan whispered into his ear.

Striding forward, he passed Eosinophil and Backwards Cap-kun. Eosinophil was looking around wildly, unsure of where everyone was. He grabbed hold of Eosinophil's hand, guiding her with him to catch up with AE-3803. He placed a hand on 3803's shoulder, making a small chain passing through. Keeping at a steady pace, they passed through to the Right Ventricle, and soon found themselves approaching the exit.

With so many cells bumping and pushing, White Blood Cell was glad that the exit was fast approaching. As they made their way out of the heart, AE-3803 inhaled deeply, walked straight over to the cart pick-up area, and grabbed a cart for the CO2 she was carrying.

Turning to look behind her, she saw White Blood Cell still holding her shoulder, with Leader-chan still on his shoulders. Behind him, he was holding Eosinophil's hand, who still had Backwards Cap-kun on her shoulders.

"Okay!" said Red Blood Cell cheerily, "everybody's here! Let's keep looking!"

"But what if it got lost in the Heart somehow?" asked Eosinophil.

"I think it would be trampled to pieces before anyone picked it up and read it," said White Blood Cell.

Eosinophil nodded. She looked slightly relieved, but she clearly would rather retrieve the book than have it destroyed.

"Don't worry big sister! We'll find it!" Leader-chan said from atop White Blood Cell.

Eosinophil nodded once again.

"Come on, we need to get moving. We don't want to cause a backup" said Red Blood Cell. The group began moving up to the lungs.

As they approached, White Blood Cell could hear a rhythmic whirring. It came in phases of two- _inhaaaaaale, exhaaaaale_.

 _ **The Respiratory System:**_ _the lungs bring in oxygen and expel carbon dioxide due to contractions of a muscle called the diaphragm. Oxygen flows through the bronchioles, or air pipes, of the lungs into microscopic sacs called alveoli, where it enters the bloodstream. The alveoli then fills with the waste product carbon dioxide, which travels the reverse path of the oxygen out of the lungs and the body._

Red Blood Cell approached an aveolus sac. She took the canisters of CO2 out of the box and placed them on the conveyor belt. She then quickly folded up the old box and placed it in a recycling pile nearby. Next to the pile were new boxes, freshly labelled and ready to use. Red Blood Cell brought one to the cart, just as freshly-filled oxygen canisters arrived on the conveyor belt. She picked up the canisters, placed them in the box, and motioned for everyone to follow her as she walked ahead.

"MAKE SURE TO STICK TOGETHER!" shouted Red Blood Cell over the noise of the various gasses rushing through the lung's bronchioles.

"WHAT?" shouted Eosinophil.

"WHAT DID YOU SAY?" Red Blood Cell replied.

"IT'S TOO LOUD IN HERE, I CAN'T HEAR YOU!" Eosinophil shouted over the roar of the lungs.

"SORRY, I DIDN'T CATCH THAT, IT'S TOO LOUD IN HERE," responded Red Blood Cell.

"LET'S KEEP GOING, IT'S TOO LOUD IN HERE!" White Blood Cell interjected.

They walked on, and the roar got quieter as they moved on. Soon they would exit the lungs and return to the Heart.

White Blood Cell was rubbing his ears when something caught his eye. Or rather, someone.

"Oh, Basophil!" shouted Red Blood Cell happily.

"Basophil-senpai!" exclaimed Eosinophil nervously. As she and White Blood Cell had learned recently, the band cell senpai who used to mentor them turned out to be none other than Basophil.

 _ **Basophils:**_ _the rarest type of white blood cell, basophils are thought to summon eosinophils and neutrophils to the scene of an infection. They also are suspected to play a role in allergic reactions and preventing blood clots. The full extent of their functions remains unknown._

"Greetings, travelers," said Basophil. "The winds of fate are upon us today."

"Hm?" asked Red Blood Cell, cocking her head.

Basophil was a strange cell. No one really had any idea what he does. He was secretive, covering his face with a black scarf and wearing a blue raincoat at all times. He always kept his hood up over his head, even though he was already wearing a blue cap and the black scarf. What's more, he always spoke in riddles and cryptic poetry, confusing almost everyone. Eosinophil was one of the few people who could understand his actual intent. U-1146 suspected that this was in part due to her continuing to practice poetry, even after maturing.

Although Basophil was so strange, finding out that he was their mysterious band cell senpai gave White Blood Cell a new respect for him. Afterall, Basophil taught him how to think carefully about his actions and nature, which served 1146 well and led him to appreciate the hard work of other cells. Basophil also taught Eosinophil many things as well. After they believed their senpai had gone forth and died, his brave actions inspired both of them to give their all in defense of the body.

It comforted White Blood Cell a little that his beloved mentor had managed to survive.

Basophil looked down to Red Blood Cell, who was almost a full head shorter than him. "Strange beasts are afoot in this land. The Cylindrical Terror approaches from the depths of an abdominal perdition, to lay waste to this world."

Basophil's voice did not change while describing this threat to the body. At least, it _sounded_ like a threat. 1146 wasn't entirely sure, Basophil tended to be a little dramatic in his word choice.

"I am glad you have come," continued Basophil, who showed no indication in his voice or his eyes that he was actually glad. "This will be a dark hour for us all."

"Senpai, are you telling us that there's an infection?" asked Eosinophil.

White Blood Cell felt Platelet's legs clamp harder around his head as she held tighter. "Big Brother, I'm scared," she said.

Backwards Cap-kun looked like he was feeling similarly.

Suddenly, the ground trembled.

Basophil looked at a spot behind Eosinophil.

"The beast approaches."

* * *

 _A/N: All medical information from Healthline, WebMD, and my memory of human anatomy._


	3. Chapter 3: Ascaris Lumbricoides

**Chapter 3:** _ **Ascaris Lumbricoides**_

The ground shook violently. Eosinophil nearly dropped Backwards Cap-kun, but she managed to regain her balance.

Suddenly, the wall behind her burst open. A thunderous roar split the air, downing out even the ever-present whir of the lungs.

 _RRRRRAAAAAAAAAAAAAAAAHHHGHHGHGHHHHHHHHH!_

 _ **Ascaris lumbricoides:**_ _a parasitic roundworm that can enter the human body through the consumption of soil infected with the parasite's eggs. The eggs will hatch in the small intestine, then migrate through the bloodstream to the lungs where they mature further. From there, the worms are coughed up and usually swallowed. They mate once in the small intestine again, and they release their eggs in the host's feces._

 _They can cause coughing, bloody mucous, vomiting, intestinal blockage, and growth impairment in children, among other things._

Red blood cells ran screaming from the blood vessel's entrance as a horrifying monster slithered through. The enormous feind was a sickly yellowish-white color, and its gaping expanded and contracted as it searched for nutrients. It had no eyes, but still seemed to know where it wanted to go as it headed towards the alveoli with another ear-splitting screech.

 _RRRRRRREEAAAAAAAAAAAAGAHGHGHGHHHHGHGGHHHH!_

She could feel the platelet on her shoulders trembling with fear. She quickly picked him from her shoulders and set him down near U-1146.

"Big sister, what are you doing?" he sobbed.

Eosinophil booped him on the nose. "Don't worry, little one," she said seriously. "I've got this."

Picking up the bident spear she always carries, she turned to face the monster. While it was true that she was weak against unicellular antigens like bacteria, and also that she had low self-esteem, Eosinophil felt nothing but determination as she stared down the beast. _I've got this_ , she thought. _It's what I was made to do._

 _ **Eosinophils:**_ _Eosinophils are a type of white blood cell that specialize in attacking and destroying multicellular parasites._

She began to walk towards the worm, her bident lowered. Despite the worm's blindness, it seemed to sense that danger was approaching as it turned to face Eosinophil. Death had come for the roundworm.

And Death wore pigtails and a pink uniform with white fluff on the inside to keep her warm.

Eosinophil came to a halt several micrometers in front of the parasite. For a moment, neither moved. The only sounds were the whir of the lungs and the screams from cells running away. Then, without warning, faster than a blink (if the worm had eyes to blink), Eosinophil pounced.

The creature roared and reared it head as Eosinophil launched herself above it and began to come down, her bident pointed straight down.

"DIE YOU PARASITE BASTARD!" she shouted.

 _RRRRRRREEEAAAAAAAAAAAAAAAAAAAAAAAHGHGHGGGGHHHHHH!_ the monster replied.

Eosinophil landed spear-first on the monster's back, the points of her bident piercing the skin and penetrating the work deep.

 _RRRREEAAAAAGHHHH!_ it protested.

It thrashed back and forth, but Eosinophil's grip did not waver. She twisted her bident further into the monster as it whipped her around. Completely unfazed, Eosinophil reached into her uniform jacket and retrieved a vial labelled "granules" as she continued to hold her spear one-handed.

 _ **Eosinophil Granules:**_ _Eosinophils have hundreds of granules filled with enzymes and proteins, the functions of which are only partially known. Eosinophils release these granules to damage and destroy parasites that infect the body._

Eosinophil threw the granule into the wound created by her spear. It broke against the worm's flesh and immediately started dissolving every bit of worm it came into contact with. As the hole around her bident widened, Eosinophil dislodged her spear and ran along the length of the worm. Every couple of micrometers she would stab the worm, before retrieving another granule from her inside jacket pocket and hurling it into the wound. The enzymes released from the smashed granules dissolved the worm's flesh and made a sizzling noise as the worm thrashed. However, its thrashing became more and more sluggish as Eosinophil ran.

 _RRREEYAAAAHGHHH_ …

When Eosinophil reached the creature's tail, she doubled back, again stabbing and throwing granules every now and then. When she returned to the monster's head, it could barely move.

 _RRREAAAaaaahghhggghhhhh_ …

And then the worm lived no more.

Eosinophil jumped down from the monster's head. She looked back and studied her handiwork.

Already the enzymes she released were breaking the worm down. Almost half of it was gone already, and she could see the worm continue to dissolve as the enzymes continued tearing it apart. Soon, it would be a mass of waste that could be easily coughed out.

Nodding she looked back around to her friends.

U-1146 was smirking, clearly admiring the result of the battle. AE-3803 was looking awestruck at Eosinophil, her brown eyes wide with admiration. Eosinophil started fidgeting. She didn't like being the center of attention. She looked over at Basophil, who remained as unreadable as ever, then down to the platelets.

Leader-chan had her eyes covered, and she was tugging on Red Blood Cell's jacket. Backwards Cap-kun, however, was looking at Eosinophil with even _more_ admiration than Red Blood Cell.

Eosinophil lowered her eyes to the ground and reached up to the bill of her cap. She pulled her cap down to further shield her face from onlookers, a habit of hers. She heard little feet running towards her.

"Big Sister Eosinophil! Big Sister Eosinophil! That was AWESOME!" shouted Backwards Cap-kun excitedly.

"R-really?" Eosinophil asked, blushing. She _really_ hated being the center of attention.

"Yeah!" Backwards Cap-kun zoomed into her line of vision and launched into a hug, wrapping his arms around her knees.

"Whoa!" she called out, using her bident to steady herself.

"The monster was like, 'Rawr,' and you were like, 'Die!' and, like, you _killed_ it! It was so cool!" Backwards Cap-kun's words spilled out of his mouth like a river.

"Y-you don't have t-to m-make such a big d-deal…" Eosinophil stuttered.

"But you're a hero! Thank you so much for your hard work!"

Eosinophil looked down at the little platelet. He was beaming up at her, and she felt her face flush.

She hated being the center of attention, but this little platelet was just soooo cute…

She knelt down and hugged Backwards Cap-kun, tears in her eyes.

"T-thank you very m-much."

"Big sister, why are you crying? You won."

Eosinophil sniffed.

"I'm crying because I'm so happy."

* * *

 _A/N: medical info from HealthLife, WebMD, and Cincinnati Children's Hospital website._


	4. Chapter 4: Regrouping

**Chapter 4: Regrouping**

Eosinophil and Backwards Cap-kun walked back to the rest of the group.

"Eosinophil-chan, you were so cool!" said AE-3803.

"Th-thanks…" Eosinophil bashfully rubbed the back of her neck.

"Yes, the plans of fate have favored us today. In this constant battle between life and death, the hands of fortune have given us this victory so that we may continue for yet another day. But who knows when we all shall arrive at the doors of death, never to wake again? Vigilance, lest we fall into the eternal abyss."

The other cells stared at Basophil. "Uhhh…"

"He's saying that we won now, but have to be careful so we don't lose in the future."

"Ohhh…" said Red Blood Cell.

Eosinophil looked up at Basophil. She remembered back when she was just a little myelocyte, she looked up to him as a band cell to be her mentor. He would read difficult books with her, and he taught her to write down hard to understand phrases in the margins. With everything she read, it was easier to understand Basophil when he talked.

She appreciated Basophil for all his help. He gave her the courage to fight to the end. She remembered when he was still a band cell, he seemed so cool and mysterious. When she first saw him, she thought his serious expression and curly mop of hair were very handsome. She couldn't admit it to anyone, even 1146, but as a myelocyte she used to have a little crush on him, at least at first. As he continued to help her, though, she lost her crush. She certainly didn't think he was romantically interesting now. However, she continued to give him the admiration one might give to a cool older cousin, or an extremely helpful mentor. He was her hero.

Even though she had always written poems since meeting him for the first time, since finding out he was still alive, she wrote much more frequently. She also looked back at her poems before, and she could see how she had improved and how her feelings about various subjects changed.

"Nevertheless, our tangle with oblivion is concluded for now. I shall take my leave." Giving a small nod, he turned to depart.

"Wait! Basophil-sama!" Red Blood Cell shouted.

"Yes, Crimson One?"

Red Blood Cell looked confused, but she decided to press on anyway. "We're looking for Eosinophil's book, have you seen it? It's pink with red flowers!"

Eosinophil turned as red as one of the flowers on her book. _Basophil-senpai CANNOT know about that!_

Basophil looked pensive for a moment. "Yes, I have seen this flowered tome before, though alas, it was many moons ago. I have not seen it in recent times."

"Oh, okay! Please tell us if you see anything!" Red Blood Cell smiled sweetly at Basophil.

"Eosinophil, is this book the place where you give your musings a permanent residence?"

Eosinophil wished she could pour a granule on herself and melt away. She looked around, and saw-

She calmed down. She saw that her friends were still confused by Basophil's way of speaking.

"Yes, senpai."

"I see. Fortunately I have no pressing obligations. I shall join this search party and assist in locating your lost book."

"W-what?! Senpai, y-you don't have t-to-"

Eosinophil was cut off as Basophil placed his hand on her shoulder.

"The words we write are some of the most precious items we can own. If you require my assistance, I would be honored to be of service to my old kouhai."

"S-senpai…" Eosinophil was touched by Basophil's words. At once, she felt like she was a myelocyte all over again, and Basophil-senpai was helping her overcome yet another obstacle in her way. He may have been strange and aloof, but he always showed he cared, in his own way. Eosinophil felt awestruck that her mentor would be so helpful to someone as awkward as herself.

"T-thank you very much!" Eosinophil blurt out, bowing.

Basophil faced the others. "Where shall we go to commence the search?"

"Let's go back to the Heart," said White Blood Cell. "From there we can spread out across the body and cover more ground."

"A sound idea. Onward, to the Temple of Sensibility, from whence the lifeblood of this world flows."

Basophil indicated a direction with his umbrella and began walking in that direction, with Red Blood Cell following after him. White Blood Cell called out after them.

"Red Blood Cell-san! Basophil-senpai!"

The two stopped and turned to face White Blood Cell.

"The Heart is that way," he said, pointing in the opposite direction.


	5. Chapter 5: The Intestines

**Chapter 5: The Intestines**

The group of six made their way back to the Heart. The giant temple loomed over them once more as they made their way to the Left Atrium.

Red Blood Cell pushed her cart to the drop-off area and picked up the box of oxygen. Her jacket was now facing bright-side-out, and she prepared to enter the Heart again. She turned back to her friends.

"Alright everybody, stay together!"

She faced towards the Heart again, and felt White Blood Cell place his hand on her shoulder. White Blood Cell, in turn, was holding onto Eosinophil's hand, who was holding onto Basophil by his umbrella handle. The platelets sat atop White Blood Cell and Eosinophil, holding tight.

Red Blood Cell inhaled deeply and closed her eyes. No matter how many times she passed through it, the Heart was always a magical place for her. It was so full of wonder. She let her breathing synchronize with the steady heartbeat coming from inside the Heart, when-

"Ah, the Heart," observed Basophil, interrupting her thoughts. "A magnificent Temple to Life. The Crossroads of Sensibility. Never ceasing, it constantly-"

"Hey, shut it ya big-mouthed dingus!" shouted a very grumpy male erythrocyte. "Show some respect for the place!"

Even though Red Blood Cell was interrupted by Basophil's musings, and she agreed that one should show the proper respect, she felt that this other erythrocyte was being quite rude to Basophil. He didn't seem to mean any harm.

She scowled at the erythrocyte, but White Blood Cell was the one who spoke. "Maybe you need to learn some respect as well. There is no need for name-calling."

The erythrocyte grumbled, but was elbowed by the cell next to him into being silent.

With the interruption over with, Red Blood Cell faced forward again. Slowly, they shuffled into the Heart. The steady beat grew louder as they entered the Left Atrium.

Moving downward, they entered the Left Ventricle. Here, more blood cells gathered than in any other area of the Heart.

 _The left ventricle is the strongest of the heart's four chambers. It expels blood into the aorta, which then branches off to go to the various parts of the body._

"Hold on!" AE-3803 whispered back to her friends. They crowd seemed to sweep them along without effort, and immediately it felt like they were zooming out of the Heart. Before Red Blood Cell could even process what had happened, she found herself at the end of the aorta, with many different paths to choose from.

Looking behind her to make sure everyone was still together, Red Blood Cell walked over to the cart pick-up area and plopped her Oxygen down.

She walked back to her friends. "Okay, so I'm due to deliver this oxygen to the small intestine. Should we split up now?"

White Blood Cell looked downward. He didn't seem eager to separate now. Fortunately for him, Eosinophil decided to speak up.

"Maybe we should split up after visiting the Small Intestine. I want to check that it's not with a certain someone first."

"Who?"

Eosinophil grimaced. "Dendritic Cell."

White Blood Cell and Red Blood Cell inhaled sharply. They both knew Dendritic's habit of stalking immune cells, taking embarrassing photographs of them, and using them to activate those same immune cells later. If Eosinophil had anything even slightly embarrassing in her book, Dendritic would be the worst person to find it.

"Yeah, we should do that," said White Blood Cell. Red Blood Cell nodded in agreement.

"It appears a consensus has been reached. Onward, we forge ahead on this noble quest." Basophil indicated a blood vessel with his umbrella and started forward.

"Mister Basophil! Wait!" shouted Leader-chan.

Basophil stopped and turned around. Leader chan pointed at a different blood vessel exit.

"That's the right exit for the small intestine."

* * *

The group made their way down to the small intestine. At various places, they could see lactic acid bacteria playing with each other.

"Oh my gosh! They're so _cute!_ " said Red Blood Cell.

The platelets scrambled down from the immune cells they were riding on and ran over to play with the lactic acid bacteria.

 _Nyu, nyuuu!_ cooed the bacteria.

"Ah, the springtime of youth, in which the little ones leap with carefree exuberance, oblivious to the harsh cruelties of fate," said Basophil.

Eosinophil and Basophil just stared at him.

"Oh my, Basophil, you have such a way with words!" came a cheery, motherly voice from behind Basophil.

"Miss Macrophage!" shouted the platelets.

"Oh, hello little ones!" said Macrophage. "It's so good to see you!"

The little platelets ran up to hug the woman in the large, flowy maid outfit.

"What brings you all to the small intestine? Oh my, there isn't a parasite about, is there?" asked Macrophage.

"We're looking for big sister Eosinophil's book!" said Leader-chan.

"Well, there was a parasite up in the lungs," said Eosinophil. "Gosh, now that I think about it, it may have come from the small intestine. I guess I was too focused on looking for my book, I forgot to think about the parasite's origin."

"Yeah, big sister Eosinophil was so cool!" exclaimed Backwards Cap-kun. "She jumped on the monster and stabbed it and then it died and just, like, disappeared."

"Oh, my! It sounds quite impressive!"

Eosinophil blushed again. "It… it's not such a big deal…"

Backwards Cap-kun turned around. "But big sister, you were soooo _cool!_ I hope I can be as strong as you someday! Then I can help my team more!"

Eosinophil felt her mitochondria twist inside her chest. _This kid is too adorable._ She wished she could adopt this precious little platelet.

"Now, Eosinophil-chan, can you tell us what this book looks like? Maybe my colleagues and I can help find it!" said Macrophage.

"O-oh, well, it… it's pink, and it has red flowers on the cover…"

Macrophage smiled sweetly. "That sounds like a lovely little book! You sure have good taste!"

"T-thank you very much, Miss Macrophage. Um, you wouldn't happen to know if Dendritic Cell has it, do you?"

"I was actually just visiting Dendritic-sama! He showed me lots of new pictures, but I don't the he found any books. Would you like me to ask-"

"NO!" Eosinophil interrupted. "N-no, thank you. I think it would be best for me to ask him in person. Thank you."

Macrophage clapped her hands together, smiling. "Of course! Of there is anything I can do to help, just ask please!"

Suddenly, Eosinophil heard Red Blood Cell screaming.

"Ey, shut your mouth!" shouted a familiar voice. "And you, what're you doing chumming it up with a non-immune cell? How many times do I have to tell you-"

"Oh, dear, I think we should intervene," suggested Macrophage.

Together, Eosinophil, Basophil, Macrophage, and the platelets went over to where AE-3803, U-1146, and now Memory T Cell were standing.

Memory T Cell, formerly Killer T Cell, was shouting in 1146's face. "-We're killers! Don't forget it!"

"Oh, wow, it seems everyone is running into each other today!" said Macrophage.

Memory T looked at everyone. "What's going on here?! What's everyone doing gathering here?!"

"Why are you outside of the thymus, Memory T Cell?" asked Eosinophil.

 _ **The Thymus:**_ _the gland which produces and stores T cells until needed by the body._

"I have special orders to be down here."

Red Blood Cell looked at U-1146, frightened. "You don't think it's Cancer again, do you?"

A gloom passed over the group. Everyone remembered how a rogue Cancer Cell nearly proliferated and threatened the body some time before. It was also common knowledge that Memory T, NK Cell, and U-1146 had faced Cancer Cell again a second time. Memory T had to use a special, last-resort technique, and U-1146 had dealt the killing blow.

What worried everyone was that Cancer's last words on both occasions were "See you again," addressed to the Neutrophil.

"Fortunately, no," said Memory T Cell. "I haven't seen any sign of that buggy bastard recently."

"Please be sure to watch your language," said Macrophage with a serene smile. "There are little ones here."

Memory T glanced down at the platelets, as U-1146 and Eosinophil both blushed. The immune cells tended to use coarse language when fighting germs, whether or not there were platelets around.

"Fine," grunted Memory T Cell.

Suddenly, the ground moved.

"WHAT THE F-" as quickly as he had forgotten his agreement, Memory T Cell was cut off as White Blood Cell clamped a hand tightly over his mouth, while also grabbing the back of Memory T's head in his hand. At the same time, Red Blood Cell quickly covered Leader-chan's ears, while Eosinophil whipped off her pink cap, undid the earflaps in one swift motion, and clamped it over Backwards Cap-kun's ears.

"LANGUAGE!" they shouted simultaneously.

The ground moved again.

"Oh, dear, this doesn't look good," said Macrophage.

"Once more, the tenuous balance of life threatens to tip into darkness. Like the hydra of old, it is not enough to destroy on head, for more shall take its place."

The ground rattled worse than ever before. White Blood Cell let go of Memory T and whipped out his knife. Eosinophil gripped her bident harder. Memory T cracked his knuckles.

The source of the tremors was revealed as another Ascaris Lumbricoides burst through the wall of the intestines.

"WHAT THE HOLY HELL IS THAT?!" shouted Memory T, eyes wide with terror.


	6. Chapter 6: Clostridium Botulinum

**Chapter 6:** _ **Clostridium Botulinum**_

The _Ascaris Lumbricoides_ in the intestines was only slightly smaller than the one in the lungs.

Which did absolutely nothing to make it less horrifying.

Eosinophil wasted no time in running towards the beast. The others ran away as fast as they could, except for Backwards Cap-kun

"YOU GO BIG SISTER!" he shouted "KILL IT HARD!"

Eosinophil didn't have time to focus on how cute Backwards Cap-kun was. She was chastising herself mentally.

 _If I wasn't so focused on my damn book, I would have known to investigate for more parasites!_

She leapt into the air, whirling her bident around. Coming down, she let out a feral cry that almost matched the worm's in intensity.

"AAAAAAAAAAAAAAHHHH!"

 _RRREEEEEEEAAAAAAAAAAAHAGHGHGHHHH!_

Her bident pierced the worm's head, and blood began spewing out. She twisted the spear, and her pink uniform started to turn a vibrant red as the blood splashed her. The worm's head fell to the ground.

Eosinophil reached into her jacket and began pulling out a granule, but the ground started rumbling again. Just as she looked in the direction of the disturbance, two more worms made their appearance.

 _Oh no… It's not just one parasite… It's an entire infestation!_

Even as this thought was forming, more worms were coming from around a bend in the intestines. She had never faced this many parasites before.

Eosinophil pulled her spear out of the worm and tugged at her cap. She made sure she was quiet enough that the platelets didn't overhear.

"Shit."

* * *

"AAAAAAAHHHH!"

It was hard to hear Eosinophil and the worms over AE-3803's screaming.

White Blood Cell scooped both of the platelets into his arms. "Red Blood Cell, hurry!"

He had only ran forward a few micrometers when a bacterium burst through the ground. It had a bulbous head, a thin torso, and several long, thin flagella. It was a bright greenish-blue, and it had several eyes dotted around its head on all sides. It had a large, gaping mouth on its torso amidst the flagella.

"HAHAHAHAHA! I'M IN! COME ON, BOYS, IT LOOKS LIKE WE HIT THE JACKPOT! NOT MUCH OXYGEN HERE!"

 _ **Clostridium Botulinum:**_ _C. botulinum is an anaerobic, gram-positive bacteria that causes the disease known as "botulism." Most often found in improperly canned goods, C. botulinum can also be found in the soil. Symptoms can include nausea, dizziness, double vision, drooping eyelids, difficulty swallowing, and in severe cases, paralysis and death. Full recovery can take weeks, and in some cases it never comes at all even once the infection is over._

 _To avoid infection, it is recommended to avoid purchasing food in cans that are dented, bulging, or deformed in any way, and to wash the tops of cans before opening them._

More bacteria like the first one burst into the area, flailing their tentacles around to move.

White Blood Cell narrowed his eyes as his radar beeped. He let down the platelets, who ran over to Red Blood Cell.

 _I know already,_ he thought.

Leaping into the air, 1146 ripped his knives from their sheaths.

"ORE ORE!" he shouted.

Landing on top of a bacterium, he stabbed down with his knives. A spray of red cytoplasm spayed his uniform and his face. He did a front flip off of the bacterium and landed gracefully on the ground. He whipped around in a circle, slashing outward in a deadly arc. 1146 heard girlish laughter as his enemies' cries faded to silence.

"Hai-yah!" chirped Macrophage as she swung her extremely oversized sword in a perfect circle, obliterating the bacteria around her.

"HUU!" shouted Memory T Cell, as he punched some bacteria in the head. A loud _crunch!_ sounded out as the bacteria crumpled, dead.

White Blood Cell heard a rumble as other Killer T Cells emerged from nearby.

"DIE, GERM BASTARDS!"

To his left, Macrophage's walkie-talkie crackled as she spoke into it. "This is Macrophage, I could be using some backup down here in the small intestine!"

"Oy, where did that useless moron Basophil sneak off to?" demanded Memory T as he pummelled another bacterium. "Lazy bastard is leaving us to do all the work!"

White Blood Cell slashed another bacterium as he frowned. "Don't talk about Basophil that way, I'm sure he knows what he's doing."

U-1146 ducked as a bacterium's flagellum nearly caught his head. Severing the appendage, he stabbed the bacterium before slashing another in one fluid motion.

"Well, he could do it with us instead of running away!" said Memory T.

U-1146 killed two more bacteria. "If you can whine, you can fight. Shut up and focus on our enemies, not our allies!"

"But-"

Memory T was cut off by a bacterium's flagellum wrapping around his arm. He immediately stopped talking and pulled the bacterium by the flagellum. Memory T whipped the bacterium around into its comrade, killing them both and severing the tentacle.

All around them, Killer T Cells, Neutrophils, and Macrophages swarmed to help, but the bacteria kept coming.

"Wha-? Oh no! My oxygen!" cried a familiar voice.

White Blood Cell looked up at the sound of AE-3803's voice. He saw her scrambling to get the oxygen canisters that had fallen from her box. She had her hands on two, and Platelet-chan held the third, but the fourth one bounced down towards him. Dodging two more bacteria, he he grabbed the canister and smashed it into one bacterium's multi-eyed head. Another grabbed the canister, and struggled to wrench it from U-1146's grasp. The canister slipped out of 1146's hands, and he accidentally opened this lid, discharging the oxygen…

"AAAAAAAAGGHHHH!" shouted the bacterium as it was hit by the life-sustaining gas.

 _Clostridium Botulinum are obligate anaerobes; this means that not only do they survive without oxygen, but oxygen is actually toxic to them. C. Botulinum can survive in low-oxygen environments, but high amounts of oxygen will poison them._

White Blood Cell could hardly believe his eyes. Oxygen was… harmful to these bacteria? The _C. botulinum_ shrank away as the canister continued to leak. White Blood Cell wasted no time; he picked up the oxygen and started chasing them back to the breach.

Already, a small band of platelets were tossing fibrin over the small breach where the bacteria were trying to enter. The immune cells, now outnumbering the bacteria, managed to kill them all and end the infection.

Macrophage wiped her brow. "Whew. Good thing we got a handle on that before it got too out of hand!" she said with a cheery smile. "If we had arrived too late, who knows what might have happened!"

Their moment of victory was short lived, as the ground continued to rumble. The _Ascaris_ were coming…


	7. Chapter 7: Ascaris Lumbricoides (Part 2)

**Chapter 7:** _ **Ascaris Lumbricoides**_ **Part II**

* * *

Red Blood Cell tried to cover the platelets with her body as best she could.

At least, until they told her they needed to go help patch the hole.

At that point, she cowered by herself by some rubble.

 _I'm such a useless cell_ , she thought. _Everyone else has a job to do, and all I can do is run away._

Of course, in her soul, she knew this wasn't true. She had a very important job: to deliver oxygen. Red Blood Cells gave their deliveries their all, and it was the job of the immune cells to protect the body so that the erythrocytes could make their deliveries.

Still, it was hard to not feel like a burden when the other immune cells jumped into action while she ran for cover. Well, at least she would give deliveries her all…

And then a stray chunk of debris hit the cart that her box of oxygen was resting on.

The box tumbled sideways and all the oxygen canisters fell out.

"Wha-? Oh no! My oxygen!" she cried.

AE-3803 dove to grab the oxygen canisters, but she only managed to catch the two closest. Fortunately, Platelet Leader-chan caught the third. But the fourth-

The fourth was heading straight for the bacteria!

Red Blood Cell watched as White Blood Cell grabbed the fourth canister and brained a bacterium with it. Then another started wrestling with him, and-

She covered her eyes. The canister broke. A quarter of her oxygen delivery was gone! Now she felt really useless.

 _RRRRREEEEEEAAAAAAAAAGGGGHGHHHHHHGHHH!_

Red Blood Cell covered her ears as the _Ascaris_ ' roar split the air. Looking up, she saw Eosinophil leaping from monster to monster, stabbing down with her spear as she landed. The monsters roared and squirmed, but it wasn't enough. There were many worms, and only one Eosinophil. It was hard enough for her to kill _one_ , let alone many! At the moment, she was only wounding them.

And annoying them.

The monsters screeched and thrashed, destroying cell homes on either side. Red Blood Cell looked behind her. Fortunately, it seemed that the immune cells were finished with the bacteria. She ran towards White Blood Cell as the monsters advanced.

Suddenly, she saw Eosinophil appear above her and land unceremoniously on the ground with the other immune cells.

 _No… there's too many… she's not strong enough!_

"RUUUNNN!" shouted 3803.

"ATTAAAACK!" shouted someone else.

Red Blood Cell plowed into White Blood Cell, confused at the new voice. She looked around, trying to see the newcomers.

" _YAAAAAHHHHHH!"_

Red Blood Cell rubbed her eyes. No, she was seeing correctly.

The newcomer- the newcomers- were all Eosinophils.

She had never seen so many in one place. She had never met any other Eosinophils besides… Eosinophil.

They all wore the same, rose pink uniform. Some had the ear flaps on their caps loose, while others tied them up like 3803's friend. Most were women with their hair tied in pigtails, but 3803 was surprised to see some men too, their pink uniforms doing nothing to dampen the bloodlust in their eyes. They all carried bidents, lowered at the worms as they charged into battle. One was even carrying the flag of the Eosinophil Division, a white banner with a black star in the top left corner, a pink bident over top of the star, and a pink stripe at the very bottom of the flag. The cell carrying it, a male Eosinophil, was acting like a commander and rallying point to the other Eosinophils. Red Blood Cell realized he was the one who had shouted the attack.

"GIVE 'EM HELL!" he commanded, and the Eosinophils responded with one cry.

"Eosinophil, do you see…" Red Blood Cell turned to her friend and trailed off. Eosinophil may have been tossed by the monsters, but she was already rushing back into the thick of battle with her sisters-and-brothers-in-arms.

"ORE ORE!" shouted the Eosinophils as the converged on the worms.

 _RRRRREEEEAAAAGHGGHHH!_ roared the monsters as they were overwhelmed.

Swarms of Eosinophils converged on each worm. It was almost impossible to see the parasites as they were engulfed by the Eosinophils, each cell stabbing the monsters with their bidents and tossing granules from their jackets into the wounds.

 _RRRREEEEAAAAGHGHHHH!_

Every now and then, Red Blood Cell caught a flash of blonde pigtails among the crowd. The swarm quickly split up to deal with the multiple worms. As soon as it was clear that one was taken care of, the remainder ran to the next one, working like a well-oiled machine. By the time the fifth worm was overtaken, the first worm that they attacked was a dead, steaming pile of goo that was dissolving quickly. The Eosinophils that killed the first worm then moved on to the sixth.

 _Wow,_ though Red Blood Cell, _those Eosinophils are super effective!_

The Eosinophil holding the flag was busy barking into a walkie-talkie. "WE NEED AS MUCH BACKUP AS WE CAN GET, THERE'S A LOT OF WORMS DOWN HERE! I DON'T CARE IF THERE'S NOT MANY, SEND EVERY EOSINOPHIL YOU GOT!"

The swarm moved systematically through the worms, killing, dissolving, and apparently even eating some of them as they went. As the continued to move, more Eosinophils appeared to help with the battle. Red Blood Cell stood transfixed until she felt a hand on her shoulder.

"Let's go, they're finishing up," White Blood Cell said.

"Already? That felt super fast!" complained Backwards Cap-kun, who was standing with Leader-chan by Red Blood Cell's legs.

"Well, it felt fast, but we already made a bunch of repairs to the hole in the vessel!" Leader-chan reminded him. "That takes a while."

Red Blood Cell blinked. "Have we been standing here a long time? I didn't notice, I was watching everything happen and time just… just… just felt like it stood still!"

White Blood Cell smiled. "Battles against invaders can feel like that sometimes. It looks like immune cells are not the only ones who can get caught up in it. Come on, let's go find Eosinophil and be on our way."

The group began walking towards the gigantic Eosinophil army. Red Blood Cell saw Macrophage and Memory T Cell in the corner of her vision. She craned her head around to search for Basophil, but he was still missing in action.

Or inaction.

She wasn't really sure what that guy did.

"By the way, what were all the Killer T Cells doing down here?" White Blood Cell asked to Memory T. "It really wasn't Cancer again, was it?"

Memory T scowled. "If it was as dangerous an enemy as Cancer, I would have told you. Just some viral infection down here. Looks like they came from whatever dirt this body picked up the worms and bacteria from. Nothing we can't handle."

"Do you need any help with that?" asked White Blood Cell.

Memory T cracked his knuckles. "Already taken care of."

The reached the mass of celebrating Eosinophils. Thanking them for their hard work, the group tried to slide through the crowd until they saw a familiar blonde just ahead of them.

"Eosinophil!" called out Red Blood Cell.

Immediately every Eosinophil within earshot looked at her.

"Oops…"

"Guys!" said Eosinophil. She made her way over to the group and was caught by Red Blood Cell giving her a big hug.

"Ohh, I'm so glad you're safe!" chirped 3803.

"Haha, thanks."

"Big Sister Eosinophil, I didn't know you had so many teammates!" Backwards Cap-kun said.

The flag-bearing Eosinophil had come over, and patted Backwards Cap-kun on the head.

"Little man, there's actually much less of us than there are Neutrophils or Erythrocytes. That's why you don't see as many of us, we're such a small percentage of the blood. But when we get together, we really get wild."

Eosinophil rubbed the back of her neck as Red Blood Cell looked at her. Even though she was a lean, mean parasite-fighting machine, Red Blood Cell wouldn't describe her as "wild." She wouldn't even describe her as "mean," it just rhymed.

"Good work, 6677," said the flag-bearer, giving Eosinophil a thumbs up.

"Eh?" squeaked Red Blood Cell.

"T-that's my number, EO-6677. I don't have to wear my number on a badge since there's so few of us, but here it might be more useful that just 'Eosinophil.' And t-thanks, 5178."

"No problem!" said the flag-bearer with a wink. "Welp, I gotta go check on the others, make sure everyone is alright. See you guys!"

"Wait!" said Red Blood Cell, "I'm curious, how did you all know to come here?"

EO-5178 stroked his chin thoughtfully. "Well, Eosinophils are kinda primed to attack worms. We also got a heads up from BA-0808, he's the one who called us."

"Who's that?" asked Red Blood Cell.

"I'm sure you've seen him before. Tall guy, wears a blue coat and a mask, kinda weird."

Memory T Cell's eyes widened. "Basophil? That slacker called you guys?!"

* * *

 _ **A/N:**_ _Medical info from_ Discover _Magazine. I also based the Eosinophil attack off of a video of Eosinophils swarming a parasitic worm, which can be found online._


	8. Chapter 8: Dendritic Cell

**Chapter 8: Dendritic**

"Yes, violent one," said a deep voice from behind the group.

All of the cells whirled around. Basophil had appeared behind them, without any warning or sound.

 _Basophils: although most of their functions are still unknown, basophils play a role in calling immune cells to the source of an infection, as well as the release of histamine to dilate the blood vessels._

"Basophil!"

Basophil eyed Memory T Cell harshly. "Be mindful of your words; you may not know the duties of others, but the individual performs according to his designation for the good of the whole. All are needed for the survival and proliferation of this world we call home."

"But where did you go?"

"It is none of your concern how I go about my duties. Be at peace with your own."

Memory T Cell blinked, absolutely confused. "Wha-?"

"The threat to this world has been extinguished. We are fortunate today to have suffered little, but the day may come where corruption consumes us all," said Basophil, ignoring Memory T.

"What is he saying?" asked Memory T.

"The abyss consumes all eventually; we must be vigilant until that fateful day, to stave off the decay of this world."

Red Blood Cell thought this was getting confusing. "Eosin- I mean, 6677, maybe we should continue looking for your book," she suggested. It was strange referring to her with a number, she had just been "Eosinophil" until now.

"Oh, uh, yeah, sure," Eosinophil stuttered. She turned to EO-5178. "Don't make a big deal out of it, but if you find a pink notebook with red flowers, please bring it to me. I really need to find it."

"Sure thing! If you don't mind, how did you lose it?"

Eosinophil scratched her chin. "I'm not sure. I don't remember where I last had it, I just noticed at some point it was gone."

EO-5178 nodded. "I understand. I'll keep an eye out. See you around, good luck finding it."

"Thanks."

The group began making their way through the Eosinophils. Memory T declined to join, since he "doesn't have time for dumb things." The Eosinophil Army also began to disperse, the threat having been neutralized.

As they continued walking, White Blood Cell said to Eosinophil, "We should probably go find Dendritic Cell and see if he knows where it is."

Eosinophil gulped. "Oh… okay…"

Red Blood Cell tapped her on the shoulder. "Hey, just wondering… is it okay if I still call you Eosinophil? It feels weird to just call you by a number."

"Oh, of course. As long as we aren't in the middle of a crowd like this, I know who you're talking to."

...

The group finally reached Dendritic Cell's home. Just from seeing the snug treehouse, the average person wouldn't understand why Eosinophil seemed so reluctant to enter the cozy-looking cottage. But the immune cells knew. Oh, they knew.

All immune cells knew personally of the horrors that Dendritic Cell hoarded. They knew of the secrets that he kept onto, long after it seemed everyone else had forgotten. The only immune cells that were immune to Dendritic himself seemed to be the macrophages, who never had a moment where they weren't graceful and elegant. In fact, they seemed to be amused by Dendritic's shenanigans.

Red Blood Cell also knew that Dendritic had enormous blackmail power over the immune cells, at least from the stories she heard from 1146. Still, she thought that maybe he was exaggerating. Dendritic Cell always seemed like a perfectly nice and friendly cell to her.

And, if she were honest, she also felt a tad curious to see what exactly Dendritic had in his possession.

Eosinophil swallowed hard and raised her hand to knock on the door. She hesitated. Bringing her hand down, she fidgeted with her collar and adjusted her cap. She prepared to knock again, then she hesitated again.

"Big Sister, what's wrong? Why don't you knock?" asked Backwards Cap-kun.

"I, uh… Dendritic is a very scary cell," Eosinophil explained.

"He's always nice to me."

The platelets were clueless of Dendritic's antics. They didn't know the true purpose behind the photos he took.

Red Blood Cell felt an idea surface. "Backwards Cap-kun, you're a strong platelet, right?"

Backwards Cap-kun beamed up at her, eyes full of determination. "Yeah!"

"Well, Big Sister Eosinophil is feeling a little scared right now. Do you think maybe you could help her? She can pick you up on her shoulders and you can knock for her."

The little platelet saluted Red Blood Cell. "Okay, Big Sister Red Blood Cell!" He then turned to Eosinophil, arms raised.

Eosinophil looked at Red Blood Cell, her face a mix of fear, relief, and warmth. No one could resist the platelets.

She squatted down, allowed Backwards Cap-kun to climb onto her back, and then stood up. Making sure she had a firm hold of his legs. Eosinophil leaned forwards a little to let Backwards Cap-kun reach the door.

He knocked.

 _Rap rap rap rap rap!_

"Mr. Dendritic Cell, we have a question to ask you!" Backwards Cap-kun shouted through the door. Eosinophil shifted him on her back.

"One minute!" came the muffled reply. The group could hear shuffling and footsteps, and the door suddenly opened from the inside.

"Welcome! Please, come in, come in!" said Dendritic Cell.

 _ **Dendritic Cells:**_ _antigen-presenting cells responsible for activating T Cells, as well as communicating between the adaptive and innate immune system._

Dendritic Cell wore a green military uniform, complete with slacks, jacket, and peaked cap. He had a white button-up shirt and black tie on under his jacket, and his cap had a golden, eight-pointed sun badge pinned above the bill. Sticking up from the band of his cap was a small leafy branch. His dark eyes were warm and kind, and his face was framed with fluffy black hair.

Eosinophil shuddered. Who knew what this psychopath was going to do?

"Would you like some snacks?" he asked.

...

As they ate some very delicious cookies, Eosinophil decided it was best to get the hard part over with.

"Dendritic Cell… I've lost an important notebook. It's pink with red flowers, have you seen it?"

Dendritic scratched his chin. "Actually, yes, I have seen it."

Eosinophil's mitochondria twisted in her chest as her face drained of color. "Y-y-y-you have?!"

"Yes, just a short while ago actually. A small lactic acid bacterium had it. I tried to get it, but the little fellow was just too fast for me, haha." Dendritic Cell grinned. "He ran off with the book and I haven't seen him or the book since."

Eosinophil's organelles felt like they were twisted as tightly as chromosomes. So, someone had finally found her book, and Dendritic hadn't seen the inside, but it had disappeared again. Of course this wasn't over yet.

"I did take a picture of the little guy. Maybe it can help you find him." Dendritic rose from the table, went into the adjacent room, and returned with a box. He plopped it on the table, and Eosinophil could see it was full of photographs. He began to rummage through them.

Immediately, Eosinophil and White Blood Cell's faces started blushing. Eosinophil flushed even deeper when she caught sight of a photograph of her, just after she had defeated the _Anisakis_. In the picture, she was blushing furiously and smiling like a crazy person while many other cells surrounded her. She only caught sight for a second before it was gone, lost in the shuffle of hundreds of other photographs.

"Mm-hm, mm-hm, oh! Miss Red Blood Cell, I think you will like this one," Dendritic said as he pulled a picture from the box and handed it to the redhead. Red Blood Cell's signature curl physically jumped as she looked at the picture, which was of U-1146 enthusiastically singing karaoke in a storage closet as Basophil walked in behind him. White Blood Cell turned as red as AE-3803's jacket as he covered his face.

"Nooooooooo…" he groaned.

"White Blood Cell, I had no idea you liked singing so much! What are your favorite songs?" asked Red Blood Cell energetically.

"Oh, and Miss Macrophage, here's one of you, elegant as ever!"

Dendritic proceeded to pull a photo of Macrophage smiling widely and posing next to… no way… NK Cell, the two of them dressed in similar frilly maids' dresses.

"Oh, and here's one of Basophil-sama…"

Sliding another photo to the platelets, Eosinophil could see a photo taken when she and U-1146 were young myelocytes. The two of them were in a rowboat with none other than Basophil as a band cell. At the time, Basophil had not yet picked up his practice of wearing a mask, and they could see his thin face and smooth skin. His light brown hair was very curly and unruly, and his eyes would be best described as _pretty_. Of course, one had to look at the photo upside down to really see it… this picture was taken one of the times the three had capsized the boat in the lake.

"Wow! Mr. Basophil-sama, is this you! You're so handsome in this picture!" said Platelet Leader-chan, smiling widely.

"I appreciate your kind words, Little One, but what is physical beauty worth if the soul is stained with corruption? What is the face but a mask we show to the outside world, hiding our true selves deep within?"

Leader-chan looked at Basophil, confused. "If your face is a mask, why are you wearing another one?"

Basophil blinked, caught off guard by this simple but profound observation. "Ah, the simpleness of youth, which takes note of occurrences that even the most experienced miss. What is more wonderful in this life?"

Red Blood Cell pointed at the two myelocytes in the boat. "White Blood Cell-san, Eosinophil-san, are these you?"

Eosinophil pulled her cap down over her eyes. "Y-yes. When we were myelocytes, we looked up to Basophilic Band Cell as a senpai."

"Oh my gosh! You two are soooo cute! I can't believe it, you were so small! Wow!" Red Blood Cell turned to Dendritic Cell. "May I keep this one as well?"

"Of course, I make multiple copies of every photo I take… Oh! Here it is!" Dendritic Cell stopped rummaging around in the box and pulled out the photo he was looking for. He handed it to Eosinophil.

The picture showed a small lactic acid bacterium with a notebook almost as big as it. It was plump and squishy, with a grey head and a white bottom.

No doubt about it, the notebook was hers. It was pink with red flowers.

"Hmm… there are trillions of bacteria in the small intestine alone, how will we find this one?"

White Blood Cell looked up from his hands and took the photograph to inspect it.

"Hmmm… I think I know a place to start. A while ago I helped a Normal Cell bring a group of lost lactic acid bacteria back home. That Normal Cell lives near the lymph nodes." He looked up at the group. "Maybe this is one of the lactic acid bacteria we helped, and it's headed towards him. It's not much, but it's a start."

Eosinophil took a deep breath. "Okay. Let's try there."

"I hope you find your book, dear. I don't know what I would do if I lost my camera," Dendritic Cell said.

 _Every Immune Cell ever would rejoice,_ Eosinophil thought dryly.

"Um… is that Memory T Cell-sama?" asked Backwards Cap-kun, pointing towards a photo in the box.

The entire group looked in. It took Eosinophil all of her willpower not to gasp, and then burst out laughing. Sure enough, among all the other embarrassing pictures, was a photograph of Memory T Cell dressed in women's clothing, complete with ostentatious makeup, a bright red sequined dress, sheer, knee-high socks held up with garters, a feather boa, and high heels. Behind him, two other Killer T Cells were also dressed in drag, having donned maid outfits. Memory T Cell was looking back at them, laughing hard.

 _So many questions…_

Eosinophil covered her mouth with her hands. She did her best not to laugh, she really did. She almost made the mistake of looking up at her colleagues, but she knew that making eye contact would break her willpower.

Her willpower was finally broken when Backwards Cap-kun said, "I didn't know he was a girl."

The dam was breached, and no one in the group stopped laughing for five minutes.


	9. Chapter 9: The Book

**Chapter 9: The Book**

The group made their way back from AE-3803's delivery in the small intestine. Macrophage had chosen to stay behind and chat with Dendritic Cell, and Basophil had split off from the group to search on his own, in case it wasn't at the Normal Cell's house. It made sense, they would cover much more ground if they weren't all in one group, but White Blood Cell wondered how much he would actually be able to search.

In any case, they were making good time up from the small intestine. After picking up more oxygen from the lungs, they continued on towards the throat, where the lymph nodes were located. Fortunately, there was an order of oxygen due in the same building as the cell they were planning to see.

 _ **Lymph Nodes:**_ _small structures in the body that act as "filters" against germs. They also contain Killer T Cells until they are to be deployed._

Eosinophil was carrying Backwards Cap-kun on her back. Despite her lean frame, she never showed any sign of tiredness or difficulty carrying him. She seemed to have grown very fond of the little platelet.

White Blood Cell smiled to himself. _The hero worship is probably helping._ Eosinophil had easily been flustered when her peers gave her praise, but when it was coming from an adorable little platelet, she seemed much more open to it. She seemed more ready to believe it.

U-1146 had always thought of Eosinophil as a little sister. She was a part of his friend group, with 2626, 4989, and 2048. They were like a family. Still, 1146 suspected that Eosinophil may have grown a little tired of being the "baby" of the group. With Backwards Cap-kun, she could feel like a big sister for once.

As for himself, he didn't mind Leader-chan riding on his shoulders one bit.

Soon, the group arrived at the throat, very close to the lymph nodes.

Red Blood Cell eyed the entrance to the lymph nodes themselves and sighed.

"What's wrong?" asked 1146.

"If I had a piece of glucose for every time I got yelled at for accidentally trying to enter the lymph nodes, I would be a very happy erythrocyte."

White Blood Cell chuckled. "Well, if Memory T Cell treats you rudely, I can just mention some details from those photographs..."

Red Blood Cell looked shocked. "You wouldn't dare!"

White Blood Cell grinned and shrugged. "You know I wouldn't. I'm not evil. Still, the look on his face if I even let slip that I knew about it, heh."

Red Blood Cell looked over into the lymph node. She could see Naive T Cell trainees running laps.

"I don't know what I've been told!"

"T CELLS THEY ARE MIGHTY BOLD!"

"I don't know but it's been said!"

"T CELLS THEY WILL KILL GERMS DEAD!"

"Sound off!

"ONE, TWO."

"Sound, off!"

"THREE, FOUR."

"Sound off!"

"ONE, TWO. THREE FOUR!"

In the middle of the field within the training grounds, the black Killer T Cell flag was flying on a tall pole. A white "T" inside of a circle, itself inside of a hexagon, stood out starkly on the dark banner.

Standing still on the edge of the field, Red Blood Cell saw Memory T eyeing the Naive T trainees. He glanced over at her and did a double take. He raised two fingers to point at his eyes, then at her, indicating that he was watching her. Red Blood Cell had no doubt that he was making sure she did not walk into the lymph node… again.

They reached the apartment building adjacent to the T Cells' training ground. They climbed up the stairs, Red Blood Cell in the front, Eosinophil and Backwards Cap-kun in the middle, and 1146 with Leader-chan bringing up the rear.

They reached the second floor and walked down the hallway. They stopped at a door that was a slightly different color than the neighbors', while Red Blood Cell continued to walk on. Her delivery was farther down the hall.

Eosinophil knocked on the door. Would this be it? Would her book finally, finally be here?

The door opened to reveal an unassuming Normal Cell. His his shaggy hair was uncombed and sticking out at odd angles, and his plain white t-shirt was simply adorned with the word "CELL." He seemed confused to see three immune cells at his door.

"Uh, hello. Hey, Mr. Neutrophil. What… is something wrong?"

"We were just wondering if you saw a lactic acid bacterium come by with a book," Eosinophil said. She pulled out the photo of the bacterium and gave it to the Cell Boy. "It looks like this."

The Cell Boy looked at the photograph. "Sorry, I haven't seen the lactic acid bacteria since I went to the intestines with Mr. Neutrophil. I haven't seen that book either. Sorry."

Eosinophil pulled down her cap and looked at the ground. "It's no problem. Sorry to bother you."

She immediately turned and walked away from the group, running down the stairs. From her shoulders, Backwards Cap-kun asked where they were going, but Eosinophil didn't answer.

White Blood Cell watched her go. "Eosinophil!" he called out, but she didn't look back.

...

White Blood Cell found Eosinophil sitting on the ground outside. Hugging her knees to her chest, she stared blankly at the ground. Backwards Cap-kun was gently shaking her shoulder, trying to encourage her.

"Don't worry, Big Sister, we'll find your book soon. Come on, we gotta keep searching."

Eosinophil buried her face into her knees. She ignored Backwards Cap-kun's renewed attempts to rouse her.

"Eosinophil, what's wrong?" asked White Blood Cell.

Eosinophil didn't respond, aside from a muffled "Hmpf."

White Blood Cell lowered Leader-chan and knelt next to Eosinophil. "Come on, it'll be okay. We'll find it, we just need to keep looking."

Eosinophil looked up at him, tears in her eyes. "No, don't you see. There are trillions of cells in this body. I'll probably never find it." She dropped her gaze, pouting. "Sorry for dragging you all into this."

"But Big Sister, we're happy to help!" Leader-chan said.

Eosinophil got up and brushed off her legs. She sighed and then started to walk away.

"Eosinophil-"

"Please, 1146, I just… I just wanna be alone right now." She turned and walked away quickly.

U-1146 felt his mitochondria sink as he watched her go. He knew this was difficult for her, not only losing her precious book, but to encounter so many setbacks in the course of finding it. Combined with the fact that someone might try to pry into her private thoughts… Well, for Eosinophil, that would be a very painful thought indeed.

Red Blood Cell emerged from the building's entrance just a few moments later. "Oh, where's Eosinophil?" she asked.

White Blood Cell looked at her sadly. "She needs to be alone right now. This search is very difficult for her…"

...

Eosinophil strolled over to an area with many picnic tables and stalls. She ordered a hot cup of tea from one of the vendors, then she moved to sit down. As she looked around for a vacant spot, a flash of white caught her eye.

"Eosinophil-chan! Eosinophil-chan!"

Seated next to an auburn-haired erythrocyte, U-4989 was waving cheerily to her, smiling broadly. Even despite her gloomy mood, Eosinophil felt her spirits rise a little. U-4989 was always good at cheering people up. She made her way over to him. Even though she wasn't up for social interaction, it would be extremely rude to just pretend like she didn't see him.

"Hello, 4989."

"Eosinophil-chan! I'm so glad to see you! I was looking for you, Basophil told me to give this to you!"

He handed her a package wrapped in brown paper. _Is this…?_

"I'm not sure what it is, but it sounded important. Then again, anything that guy says sounds like a matter of life or death." He turned to the erythrocyte seated next to him. "One time, I was behind him in line when he ordered tea. It sounded like that tea would decide the fate of the world."

The erythrocyte next to him laughed, playing absentmindedly with her long plait of hair. Eosinophil didn't notice her, however. She was too busy staring at this suspiciously book-sized package

Eosinophil looked up at 4989. "Basophil-senpai gave this to you? How did he get it?"

This time, the erythrocyte spoke up. "He mentioned an eosinophil gave it to him. I guess one of your colleagues wanted to give it to you, but had to take care of something else first."

Eosinophil looked at the erythrocyte, her mind running a mile a minute. " _He got it from an eosinophil?"_ she thought. _But Basophil-senpai's words often have double meanings. Does he mean he took it from me?_ Eosinophil didn't know what to think.

"I should probably get back to my deliveries. See you, 4989!" Turning to Eosinophil, she said, "It was nice to meet you, Eosinophil-sama." Bowing to Eosinophil, she made her way back to the blood vessel.

"See you, AC!" 4898 waved cheerily after her. Looking back to Eosinophil, he smiled. "I was just hanging out with her on my break. I should get back to patrolling. See ya!" He gave her a wink and was off.

Eosinophil sat at the table alone. Looking around, she carefully opened the package. Inside was…

No…

Yes!

 _Her book!_

She finally found her book!

She ran her gloved hand over the pink cover adorned with red flowers. It had been a very long time since she had first gotten it, and it had a few scratches and some wear, but it was her book. She ran her thumb down the spiral binding. _Plink-plink-plink!_

She opened the cover to the first page. In a child's large, shaky handwriting, the first page said simply: _This book belongs to EO-6677_.

A slip of paper fell out from the back cover. Frowning, Eosinophil picked it up. It wasn't lined like the pages in her notebook. It wasn't white either, it was actually a light brown. She flipped it over. In loopy, elegant cursive, there was a note addressed to her.

 _Dear Kouhai,_

 _Upon my travels I chanced upon your book. The warrior EO-5178 was in possession of it. According to him, the lactic acid bacterium handed it to him shortly after the battle. When we met, he promptly handed it over to me._

 _Though I was curious, I did not look inside at all. These are your thoughts, and are not meant for the eyes of anyone else until you decide you are ready. Even the greatest poets have had to make rewrites._

 _Do not be so timid, little one. We cells are all one in this body. We should always endeavor to lift others up. If I am not mistaken, your peers would be more than happy to do so._

 _Keep writing._

 _Sincerely,_

 _Your Senpai,_

 _BA-0808_

Eosinophil sniffled and wiped a tear from her eye as she finished reading the letter. Even after all this time, she still looked up to Basophil for guidance. Even now, he was her mentor, her senpai. She may not have had a crush on him anymore, but all at once she felt like a little myelocyte all over again.

She ruffled through a pocket in her jacket and found a paper clip. Tenderly, she clipped the letter to the back cover, so that it wouldn't fall out. Now, she could reread it whenever she liked.

She took a sip of her tea and smiled. Then, clutching her book to her chest, she rose from the table and began walking back the way she had come.

She should tell her friends she had found it, so that they knew they wouldn't have to keep looking.

With an extra spring in her step, she started to jog back to the lymph nodes. She couldn't wait to share the good news with her friends.

 _ **A/N:**_ _I would like to give a huge shoutout to Mira Avis, another author here. The blood cell seen with U-4989 above is her OC, as seen in her stories_ Realisations _and_ Hearts and Minds _. Her stories are amazing, and she is a very kind person who has given me lots of ideas and info for new stories! I highly recommend checking her out, her fictions_


	10. Epilogue

**Epilogue**

The sand by the lake was warm and calm, just perfect for sitting and writing. Eosinophil had taken off her knee-high boots and rolled up her pant legs, enjoying the feel of the sand between her toes. She braced her back against a tree, and her book against her legs. Sticking her tongue out slightly, she jotted down a few words.

From a distance, U-1146 and AE-3803 watched their friend. It was a pleasant day in the bone marrow. The young erythroblasts were playing in the Erythrocyte Academy, while myeloblasts were sparring at the Immune Cell Training Ground. There were no major threats at the moment. They could simply relax.

It had been a while since Eosinophil had found her book. White Blood Cell was very happy for his friend.

While he was watching, he saw a small group of neutrophilic myelocytes walking along the beach, joined by an eosinophilic myelocyte. As they walked, they saw Eosinophil sitting under the tree and went over to her.

...

"Big Sister, Big Sister, what are you doing here?"

Eosinophil looked up. In front of her were three neutrophilic myelocytes and an eosinophilic myelocyte. They were all very young and very small. The eosinophilic myelocyte was the smallest, her pink t-shirt extremely baggy on her little frame, and her brown hair tied into two little pigtails. The tallest neutrophilic myelocyte was a full head taller than the eosinophilic myelocyte, with a lanky frame and hair so fluffy and long it would have put both 2626 and 4989 to shame with how unruly it was and how much of his face it covered. The other two neutrophilic myelocytes were in the middle height-wise. One had neatly combed hair, while the other had his hair buzzed short. All four myelocytes had slightly chubby cheeks, being so young.

Eosinophil blinked. They were all… so… cute…

"Big Sister?" the Eosinophilic myelocyte asked, shaking Eosinophil from her surprise.

"Oh, I- I'm just…" Eosinophil quickly closed her book, embarrassed that the young cells might see. Then, she remembered.

She remembered Basophil's note, about how she shouldn't be so scared to let others see what she wrote.

She remembered how much Backwards Cap-kun looked up to her on her journey to find the book.

She remembered how much she and 1146 looked up to Basophil-senpai, who always gently helped them with whatever they asked.

Eosinophil often thought lowly of herself. She was often awkward and timid. Even as a myelocyte, she felt weak.

But she was no longer a myelocyte. She was an adult now, and these little myelocytes were curious as to what she was doing. Just like she was curious what Basophil was doing so long ago.

Clearing her throat, she opened her book up again. "I was just writing some haikus."

"Haikus?" asked the tall, fluffy headed myelocyte, cocking his head.

"Yeah. They're a type of poem."

"Wow… poems?" The eosinophilic myelocyte looked up at her with sparkling eyes. Had she once looked at Basophil like this?

"Yeah. I can show you, if you like."

The little brown-haired myelocyte stared into Eosinophil's eyes with burning admiration. "Wow! Really? You'd really show us?"

"O-of course. Here. A haiku is split up into three lines of five syllables, seven syllables, then five syllables again…"

…

"Oh my gosh, she's teaching the little myelocytes! That's so cute!"

White blood cell smiled. "You know, Basophil used to help us a lot like she's helping them now."

Red Blood Cell looked up at him. "He did?"

"Yes. We approached him wanted to learn more, and he often spent time teaching us things. He's the one who inspired me to be the best Immune Cell I could be, and the one who inspired Eosinophil to write poetry, and also to fight no matter what."

"Wow, that's so sweet!"

"Quite. It looks like Eosinophil is keeping the cycle going. Who knows, maybe she'll inspire those myelocytes to be good protectors one day."

"I'm sure they'll be great. Especially with someone as great as Eosinophil helping them!"

The two looked back at Eosinophil. She had torn some blank pages from her book and given them to the myelocytes to write on. She was busy helping the little brown-haired myelocyte, pointing at something in the book and comparing it to what the myelocyte had written.

White Blood Cell turned to Red Blood Cell. "It's quite nice at the moment. Why don't we go out on the lake. We used to have a lot of fun with Basophil-senpai rowing in the boat together."

Red Blood Cell smiled up at him. "That sounds like a great idea!"

They walked off to the lake. Under the tree, four myelocytes started to get to know their new senpai.

 _The End._


End file.
